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Adrenocortical
The adrenal cortex is the outer region and also the largest part of an adrenal gland. It is divided into three separate zones: zona glomerulosa, zona fasciculata and zona reticularis. Each zone is responsible for producing specific hormones. It is also a secondary site of androgen synthesis. – "Adrenal Gland" Layers The adrenal cortex comprises three main zones, or layers that are regulated by distinct hormones as noted below. This ''anatomic zonation'' can be appreciated at the microscopic level, where each zone can be recognized and distinguished from one another based on structural and anatomic characteristics. ;Zona glomerulosa :The outermost layer, the zona glomerulosa is the main site for the production of aldosterone, a mineralocorticoid. The synthesis and secretion of aldosterone are mainly regulated by the renin–angiotensin–aldosterone system. The zona glomerulosa cells express a specific enzyme aldosterone synthase (also known as CYP11B2). Aldosterone is large ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Reticular Layer
The adrenal cortex is the outer region and also the largest part of an adrenal gland. It is divided into three separate zones: zona glomerulosa, zona fasciculata and zona reticularis. Each zone is responsible for producing specific hormones. It is also a secondary site of androgen synthesis. – "Adrenal Gland" Layers The adrenal cortex comprises three main zones, or layers that are regulated by distinct hormones as noted below. This ''anatomic zonation'' can be appreciated at the microscopic level, where each zone can be recognized and distinguished from one another based on structural and anatomic characteristics. ;Zona glomerulosa :The outermost layer, the zona glomerulosa is the main site for the production of aldosterone, a mineralocorticoid. The synthesis and secretion of aldosterone are mainly regulated by the renin–angiotensin–aldosterone system. The zona glomerulosa cells express a specific enzyme aldosterone synthase (also known as CYP11B2). Aldosterone is large ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Adrenocorticotropic Hormone
Adrenocorticotropic hormone (ACTH; also adrenocorticotropin, corticotropin) is a polypeptide tropic hormone produced by and secreted by the anterior pituitary gland. It is also used as a medication and diagnostic agent. ACTH is an important component of the hypothalamic-pituitary-adrenal axis and is often produced in response to biological stress (along with its precursor corticotropin-releasing hormone from the hypothalamus). Its principal effects are increased production and release of cortisol by the cortex of the adrenal gland. ACTH is also related to the circadian rhythm in many organisms. Deficiency of ACTH is an indicator of secondary adrenal insufficiency (suppressed production of ACTH due to an impairment of the pituitary gland or hypothalamus, cf. hypopituitarism) or tertiary adrenal insufficiency (disease of the hypothalamus, with a decrease in the release of corticotropin releasing hormone (CRH)). Conversely, chronically elevated ACTH levels occur in primary a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Zona Glomerulosa
The ''zona glomerulosa'' (sometimes, glomerular zone) of the adrenal gland is the most superficial layer of the adrenal cortex, lying directly beneath the renal capsule. Its cells are ovoid and arranged in clusters or arches (''glomus'' is Latin for "ball"). In response to increased potassium levels, renin or decreased blood flow to the kidneys, cells of the ''zona glomerulosa'' produce and secrete the mineralocorticoid aldosterone into the blood as part of the renin–angiotensin system.Marieb Human Anatomy & Physiology 9th edition, chapter:16, page:629, question number:14 Although sustained production of aldosterone requires persistent calcium entry through low-voltage activated Ca2+ channels, isolated ''zona glomerulosa'' cells are considered nonexcitable, with recorded membrane voltages that are too hyperpolarized to permit Ca2+ channels entry. However, mouse ''zona glomerulosa'' cells within adrenal slices spontaneously generate membrane potential oscillations of low pe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cortisol
Cortisol is a steroid hormone, in the glucocorticoid class of hormones. When used as a medication, it is known as hydrocortisone. It is produced in many animals, mainly by the '' zona fasciculata'' of the adrenal cortex in the adrenal gland. It is produced in other tissues in lower quantities. It is released with a diurnal cycle and its release is increased in response to stress and low blood-glucose concentration. It functions to increase blood sugar through gluconeogenesis, to suppress the immune system, and to aid in the metabolism of fat, protein, and carbohydrates. It also decreases bone formation. Many of these functions are carried out by cortisol binding to glucocorticoid or mineralocorticoid receptors inside the cell, which then bind to DNA to impact gene expression. Health effects Metabolic response Metabolism of glucose In general, cortisol stimulates gluconeogenesis (the synthesis of 'new' glucose from non-carbohydrate sources, which occurs mainl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aldosterone
Aldosterone is the main mineralocorticoid steroid hormone produced by the zona glomerulosa of the adrenal cortex in the adrenal gland. It is essential for sodium conservation in the kidney, salivary glands, sweat glands, and colon. It plays a central role in the homeostatic regulation of blood pressure, plasma sodium (Na+), and potassium (K+) levels. It does so primarily by acting on the mineralocorticoid receptors in the distal tubules and collecting ducts of the nephron. It influences the reabsorption of sodium and excretion of potassium (from and into the tubular fluids, respectively) of the kidney, thereby indirectly influencing water retention or loss, blood pressure, and blood volume.Marieb Human Anatomy & Physiology 9th edition, chapter:16, page:629, question number:14 When dysregulated, aldosterone is pathogenic and contributes to the development and progression of cardiovascular and kidney disease. Aldosterone has exactly the opposite function of the atrial n ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mesoderm
The mesoderm is the middle layer of the three germ layers that develops during gastrulation in the very early development of the embryo of most animals. The outer layer is the ectoderm, and the inner layer is the endoderm.Langman's Medical Embryology, 11th edition. 2010. The mesoderm forms mesenchyme, mesothelium, non-epithelial blood cells and coelomocytes. Mesothelium lines coeloms. Mesoderm forms the muscles in a process known as myogenesis, septa (cross-wise partitions) and mesenteries (length-wise partitions); and forms part of the gonads (the rest being the gametes). Myogenesis is specifically a function of mesenchyme. The mesoderm differentiates from the rest of the embryo through intercellular signaling, after which the mesoderm is polarized by an organizing center. The position of the organizing center is in turn determined by the regions in which beta-catenin is protected from degradation by GSK-3. Beta-catenin acts as a co-factor that alters the activity of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Neuroendocrine
Neuroendocrine cells are cells that receive neuronal input (through neurotransmitters released by nerve cells or neurosecretory cells) and, as a consequence of this input, release messenger molecules ( hormones) into the blood. In this way they bring about an integration between the nervous system and the endocrine system, a process known as neuroendocrine integration. An example of a neuroendocrine cell is a cell of the adrenal medulla (innermost part of the adrenal gland), which releases adrenaline to the blood. The adrenal medullary cells are controlled by the sympathetic division of the autonomic nervous system. These cells are modified postganglionic neurons. Autonomic nerve fibers lead directly to them from the central nervous system. The adrenal medullary hormones are kept in vesicles much in the same way neurotransmitters are kept in neuronal vesicles. Hormonal effects can last up to ten times longer than those of neurotransmitters. Sympathetic nerve fiber impulses sti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Glucocorticoid
Glucocorticoids (or, less commonly, glucocorticosteroids) are a class of corticosteroids, which are a class of steroid hormones. Glucocorticoids are corticosteroids that bind to the glucocorticoid receptor that is present in almost every vertebrate animal cell. The name "glucocorticoid" is a portmanteau (glucose + cortex + steroid) and is composed from its role in regulation of glucose metabolism, synthesis in the adrenal cortex, and its steroidal structure (see structure below). Glucocorticoids are part of the feedback mechanism in the immune system, which reduces certain aspects of immune function, such as inflammation. They are therefore used in medicine to treat diseases caused by an overactive immune system, such as allergies, asthma, autoimmune diseases, and sepsis. Glucocorticoids have many diverse ( pleiotropic) effects, including potentially harmful side effects. They also interfere with some of the abnormal mechanisms in cancer cells, so they are used in high doses ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
11-deoxycorticosterone
11-Deoxycorticosterone (DOC), or simply deoxycorticosterone, also known as 21-hydroxyprogesterone, as well as desoxycortone ( INN), deoxycortone, and cortexone, is a steroid hormone produced by the adrenal gland that possesses mineralocorticoid activity and acts as a precursor to aldosterone. It is an active (Na+-retaining) mineralocorticoid. As its names indicate, can be understood as the 21- hydroxy-variant of progesterone or as the 11- deoxy-variant of corticosterone. ''DOCA'' is the abbreviation for the ester 11-deoxycorticosterone acetate. Biological activity DOC is a potent mineralocorticoid but is virtually devoid of glucocorticoid activity. However, 11β-hydroxylation of DOC produces corticosterone and confers glucocorticoid activity, along with 10-fold reduced mineralocorticoid activity. In addition to its mineralocorticoid activity, DOC has been found to possess one-third to one-tenth the potency of progesterone as a progestogen when administered systematicall ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dehydroepiandrosterone
Dehydroepiandrosterone (DHEA), also known as androstenolone, is an endogenous steroid hormone precursor. It is one of the most abundant circulating steroids in humans. DHEA is produced in the adrenal glands, the gonads, and the brain. It functions as a metabolic intermediate in the biosynthesis of the androgen and estrogen sex steroids both in the gonads and in various other tissues. However, DHEA also has a variety of potential biological effects in its own right, binding to an array of nuclear and cell surface receptors, and acting as a neurosteroid and modulator of neurotrophic factor receptors. In the United States, DHEA is sold as an over-the-counter supplement, and medication called prasterone. Biological function As an androgen DHEA and other adrenal androgens such as androstenedione, although relatively weak androgens, are responsible for the androgenic effects of adrenarche, such as early pubic and axillary hair growth, adult-type body odor, increased oilin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Corticosterone
Corticosterone, also known as 17-deoxycortisol and 11β,21-dihydroxyprogesterone, is a 21-carbon steroid hormone of the corticosteroid type produced in the cortex of the adrenal glands. It is of minor importance in humans, except in the very rare case of congenital adrenal hyperplasia due to 17α-hydroxylase deficiency. Roles In many species, including amphibians, reptiles, rodents and birds, corticosterone is a main glucocorticoid, involved in regulation of energy, immune reactions, and stress responses. However, in humans, cortisol is the primary glucocorticoid that is produced primarily in the zona fasciculata of the adrenal cortex. Corticosterone has only weak glucocorticoid and mineralocorticoid potencies in humans and is important mainly as an intermediate in the steroidogenic pathway from pregnenolone to aldosterone. Corticosterone is converted to aldosterone by aldosterone synthase, found only in the mitochondria of glomerulosa cells. Glomerulosa cells are ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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